Best available cop



BEST AVAILABLE COF" (No Model.)

A. MUIRHEAD.

Insulated Telegraph W'reg. A

No. 230,803. Patented Aug. 3,1880.

N.PETERS, PHoTo-LJYHOGRAFHEF. WASHINGTON. D C.

y l effects of sea-water and to the attacks of ani esst AVAILABLE coe Unirse STATES PATENI`g OFFICE..

ALEXANDER MUIRHEAD, OF OAKWOOD, FARQUHAR ROAD, UPPER NORVV OOD, LONDON, ENGLAND.

INSU LATED TELEGRAPH-WIRE.

SPECIFICATION formingpart of Letters Patent No. 230,803, dated August 3, 1880.

Application filed March 24, 1880. (No model.) v

To 'all whom 'it may concern:

Be it known that I, ALEXANDER MUIRHEAD, a subject of the Queen of Great Britain, do-

in g business at 29 Regency street, Westmin.

`To protect the wires from mechanical injury,

I serve' them outside with iibrous material impervious to sea-water and the attack of animalculae.

I have discovered as most suitable for this purpose gumootie ber, which is obtained from the species of palm called the gomuti77 palm, found in what are known in England as the Straits settlements, being the countries contiguous to the Straits of Malacca, off the south of India. This ber forms a sort of nest in which the nut of the palm rests, and is collected after the fruit is gathered, and made iuto rope, dce. It is impervious to the malculae, from which all other kinds of fibrous material 'in that locality suffer. It is found from long experience to be more durable than hemp, jute, or any other such material hitherto used.

For further protection from mechanical injury I partially vulcanize or case-harden the insulating material, negrite. This I do after coating the wires by exposing the outside of the coating for a short-time to the action of sulphur, either in solution in chloride of sulphur, or in a sulphur-vapor bath in well known methods of vulcanizing.

For the purpose of underground telegruphy, wires protected as above are laid in metallic or other pipes in the usual way.

To prevent variations in the electrical condition of these wires I further protect them by filling up the pipes with soluble silicates, such as water-glass. At frequent intermediate points in the circuitot' such an underground system I insert tcst-boxes constructed of cast-iron and made air-tight by means of covers screwed down on vulcanized-rubber cushions.

To protect the wires from moisture, l place in the lower portion of these test-boxes a chamber containing chloride of calcium, quieklime, or other absorbent of moisture, and provided with a perforated cover, diaphragm, or partition, which separates it from that part ol the test-box through which the wires pass.

In the drawing, A is the test-box, l the airtight cover resting on the cushions O. l) is the perforated diaphragm, E the chamber containing the desiecant. f

It is obvious that a serving with fibrous material impervious to sea-water and to the attack of animaleulm may be advantageously used with anyl description of insulating material, though l prefer for the purpose the insulator and serving of fiber hereinbefore described.

What I claim as new, and desire to secure by Letters Patent, is

1. The hereinbetore-described method oi' protecting electric-telegraph wires which consists in serving them with a wrapping of guinootie ber, substantially as herein set forth.

2. The hereinbetoredescribed method of protecting electric-telegraph wires insulated or covered with negrite, which consists in partially vulcanizing or case-hardening the outside of thecoverin g of negritc, and then serving' it with a wrapping of guinootic fiber, substantially as herein set forth.

3. The hereinbetore-described method of protecting underground electric-telegraph wires, which consists in laying them in pipes or troughs filled up with soluble silicates, substantially as herein set forth.

4. An electric wire served with a wrapping of gumootie ber, substantially :is set fort-h.

5. An electric wire insulated or covered with ncgrite, partially vulcanized or easemed on the outside, and provided with :t I In Witness whereof I have herennto sub- .fing of gninootie fiber, substantially :is set. scribed my nznne this 27th day of liehiua-ry, 1o

Jrth. I issn.

6. Thehereinbefore-deseribed method of pro- T 1 5. teeting underground electric-telegraph wires7 ALE MUIRHEAD' which consists in surrounding them with solu- Witnesses: ble silicates and providing for testing then] :Lt GHAS. EDGAR MILLS, intervals, substantially as set forth. XVILLIAM D. WARD. 

